There exist in the art numerous forms and methods of fabricating brushes intended for use in applying a flowable fluid, typically liquid, to a workpiece. Among such brushes is that, and the method of making the article, disclosed in U.S. application Ser. No. 222,808 filed July 22, 1988 to McNab. The McNab brush is formed of a plurality of bristles or filaments that are assembled into a tuft and are secured together at one end to define the head or head section of the brush. A particularly advantageous feature of the McNab brush is the further provision of a substantially flexible, relatively thin-walled distribution channel that axially extends through a peripherally-interior portion of the tuft from the head section toward the distal ends of the filaments. This distribution channel provides an internal, substantially flexible passageway for feeding flowable fluid from the head section of the brush to the filaments proximate their distal ends for selective application of the fluid to a workpiece. An alternate method of making the McNab brush is disclosed in U.S. application Ser. No. 400,983, filed Aug. 31, 1989, of Kay.
As described in each of these earlier disclosures, the distribution channel of the brush is fabricated by fusing or melting of the heat-fusible synthetic material of the filaments. Accordingly, in order to achieve the desired relatively thin-walled construction and substantial flexibility of the distribution channel sidewall, the material fusing time and temperature must be carefully controlled. Furthermore, the production volume of brushes that may be commercially manufactured in a given time period may be limited by, for example, the heating and cooling requirements of the fabrication process. Finally, the need to form the distribution channel through heat fusing of the filaments material limits the selection of materials from which such brushes are formable.